Android Open Source - EulerSolutions Completed Problems

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Back to project page EulerSolutions.

License

The source code is released under:

MIT License

Java Source Code

package com.eulersolutions.model;
// ww w  .  j a v a2s. c  om
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.JSONTokener;

import com.eulersolutions.controllers.R;

import android.content.Context;
import android.util.Log;

public class CompletedProblems {
  
  private static final String TAG = "EulerSolutions-CompletedProblems";
  private static final int[] IDS = {R.raw.problem001,
                    R.raw.problem002,
                    R.raw.problem003};
  private ArrayList<ProblemSummary> problems = new ArrayList<ProblemSummary>();
  
  private Context parentContext;
  @SuppressWarnings("rawtypes")
  public CompletedProblems(Context newContext)
  {
    parentContext = newContext;
    for(int id : IDS)
    {
      InputStream inputStream = parentContext.getResources().openRawResource(id);
      BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
      StringBuffer buffer = new StringBuffer("");
      JSONObject object = null;
      int problemId = -1;
      String name = "";
      String description = "";
      String example = "";
      String solution = "";
      String eulerSolution = "";
      ArrayList<String> inputStrings = new ArrayList<String>();
      String calcName = "";
      ProblemCalculator calculator = null;
      ProblemSummary newItem = null;
      
      Class calcClass = null;
      
      try
      {
        String line = "";
        while((line = reader.readLine()) != null)
        {
          buffer.append(line);
        }
        
        object = (JSONObject) new JSONTokener(buffer.toString()).nextValue();
        problemId = object.getInt("id");
        name = object.getString("name");
        description = object.getString("description");
        example = object.getString("example");
        calcName = object.getString("calculator");
        
        JSONArray jsonArray = object.getJSONArray("solutions");
        solution = buildSolution(jsonArray.getJSONArray(0));
        eulerSolution = buildSolution(jsonArray.getJSONArray(1));
        
        jsonArray = object.getJSONArray("inputStrings");
        for(int index = 0; index < jsonArray.length(); index++)
        {
          inputStrings.add(jsonArray.getString(index));
        }
        
        calcClass = Class.forName("com.eulersolutions.model." + calcName);
        Constructor constructor = calcClass.getConstructor();
        calculator = (ProblemCalculator) constructor.newInstance();
        
        newItem = new ProblemSummary(name, description, example,
            solution, eulerSolution, inputStrings, calculator,
            inputStrings.size(), problemId);
        problems.add(newItem);
      }
      catch(IOException e)
      {
        Log.i(TAG, "IO Reading Error");
        e.printStackTrace();  
      }
      catch(JSONException e)
      {
        Log.i(TAG, "JSON read error");
        e.printStackTrace();
      }
      catch(ClassNotFoundException e)
      {
        Log.i(TAG, "Calc class not found");
        e.printStackTrace();
      }
      catch(NoSuchMethodException e)
      {
        Log.i(TAG, "Calc class could not find constructor");
        e.printStackTrace();
      }
      catch (IllegalArgumentException e) 
      {
        Log.i(TAG, "Calc class Illegal argument in constructor");
        e.printStackTrace();
      }
      catch (InstantiationException e) 
      {
        Log.i(TAG, "Calc class instance exception");
        e.printStackTrace();
      }
      catch (IllegalAccessException e)
      {
        Log.i(TAG, "Calc class illegal access");
        e.printStackTrace();
      }
      catch (InvocationTargetException e)
      {
        Log.i(TAG, "Calc class invocation target exception");
        e.printStackTrace();
      }
    }
  }
  
  private String buildSolution(JSONArray solutionArray) throws JSONException
  {
    StringBuilder builder = new StringBuilder();
    for(int index = 0; index < solutionArray.length(); index++)
    {
      builder.append("     ");
      builder.append(solutionArray.getString(index));
      builder.append(System.getProperty("line.separator"));
    }
    return builder.toString();
  }
  
  public ArrayList<ProblemSummary> getCompletedProblems()
  {
    return problems;
  }
  
  @Deprecated
  public static ArrayList<ProblemSummary> createCompletedProblems()
  {
    Log.i(TAG, "Entered createCompletedProblems");
    String name;
    String description;
    String example;
    String solution;
    String eulerSolution;
    ArrayList<String> inputStrings;
    ProblemCalculator calculator;
    ProblemSummary newItem;
    int id;
    
    ArrayList<ProblemSummary> toReturn = new ArrayList<ProblemSummary>();
    
    //add problem one
    inputStrings = new ArrayList<String>();
    name = "Multiples of A and B";
    description = "Given a maximum value and two multiples (all positive),"
        + " find the sum of the all of the multiples.";
    example = "For example, consider a max value of 17 and the multiples"
        + " 3 and 4. The multiples of 3 and 4 less than 17 are 3, 4, 6, 8, "
        + "9, 12, 15, and 16. Their sum is 73.";
    solution = "Using modulus division, we can find the greatest number that divides and move from there.";
    eulerSolution = "My solution matched the Euler Solution";
    inputStrings.add("First Multiple: ");
    inputStrings.add("Second Multiple:");
    inputStrings.add("Max Value: ");
    calculator = new MultiplesABCalculator();
    id = 1;
    newItem = new ProblemSummary(name, description, example,
        solution, eulerSolution, inputStrings, calculator, inputStrings.size(), id);
    toReturn.add(newItem);
    
    //add problem two
    inputStrings = new ArrayList<String>();
    name = "Even Fibonnaci Numbers";
    description = "Given a maximum value, find the sum of all of the even "
        + "Fibonnaci numbers less than that value";
    example = "For example, consider a max value of 9. The Fibonnaci numbers"
        + " less than 9 are 1, 2, 3, 5, 8. Summing the even numbers, "
        + "we get 8 + 2 = 10.";
    solution = "We can prove that starting at the second number, ever third term afterwards is even."
        + " Then we use Binet's formula for finding the nth Fibonnaci value and sum the values.";
    eulerSolution = "Not sure if my solution matched Euler's yet";
    inputStrings.add("Maximum Value: ");
    calculator = new EvenFibonacciNmCalculator();
    id = 2;
    newItem = new ProblemSummary(name, description, example,
        solution, eulerSolution, inputStrings, calculator, inputStrings.size(), id);
    toReturn.add(newItem);
    
    return toReturn;
  }
}

Java Source Code List

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